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| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 6 |
| 3 | 19 |
| 4 | 70 |
| 5 | 262 |
| 6 | 1023 |
| 7 | 4094 |
| 8 | 16818 |
| 9 | 69945 |
| 10 | 294922 |
| 11 | 1259081 |
| 12 | 5426730 |
| 13 | 23561608 |
| 14 | 103046709 |
| 15 | 453659247 |
| 16 | 2007599774 |
| 17 | 8925829461 |
| 18 | 39864238925 |
| 19 | 178747571197 |
| 20 | 804199297973 |
| 21 | 3629751750042 |
| 22 | 16432391497625 |
| 23 | 74589692974370 |
| 24 | 339393460911899 |
| 25 | 1547853224158976 |
| 26 | 7074306420083226 |
| 27 | 32394805350463378 |
[1,2,6,19,70,262,1023,4094,16818,69945,294922, 1259081,5426730,23561608,103046709,453659247, 2007599774,8925829461,39864238925,178747571197, 804199297973,3629751750042,16432391497625, 74589692974370,339393460911899,1547853224158976, 7074306420083226,32394805350463378] |